Novel low-cavitation sectional multi-stage pump

Abstract

The invention relates to the technical field of water pumps, in particular to a novel low-cavitation sectional multi-stage pump. Two smaller first-stage impellers are adopted on the premise that the design flow of the two first-stage impellers is 1 / 2 of the design flow of the water pump; the two first-stage impellers are installed in series and are each independently provided with a guide vane. A first guide vane outlet and a second guide vane outlet are communicated through a runner cavity, so that the parallel operation state of two small first-stage impellers is realized; therefore, a single first-stage impeller only needs to bear 1 / 2 of the running flow of the pump, and the cavitation performance of the first-stage impeller can be greatly reduced; and finally, the net positive suction head can be consistent with that of a traditional first-stage double-suction stage type multi-stage pump, but the structure is more compact and simpler, and the efficiency is higher.

Description

Technical Field

[0001] The present invention relates to the technical field of water pumps, and in particular to a novel low-cavitation segmented multi-stage pump. Background Art

[0002] In traditional segmented multi-stage pumps, the first-stage impeller is a single-suction impeller with a high NPSH. Subsequently, in order to reduce the NPSH, an inducer design was introduced, but the inducer's improvement on the cavitation performance of the first-stage impeller was always limited. Later, the industry introduced a double-suction impeller design for the first-stage impeller, which greatly reduced the cavitation performance. However, since the double-suction impeller needs to be equipped with a volute and the pipe is re-set to introduce the water flow from the volute outlet into the secondary impeller inlet, the flow path is very complex and difficult to manufacture. The quality is not easy to guarantee, and due to the excessive turns of the water flow, there will be a certain amount of energy loss, so the efficiency will be reduced. Summary of the Invention

[0003] The object of the present invention is to solve the deficiencies of the prior art and to provide a multi-stage pump with low NPSH which comprises two first-stage impellers running in parallel.

[0004] To achieve the above object, the present invention provides a new type of low cavitation segmented multistage pump, comprising The casing flow guide structure includes a pump cover, a water inlet section, several middle sections and a water outlet section. The water inlet section, the middle section and the water outlet section are sealed and connected in sequence and fixed by through-rod bolts that penetrate through each section. The rotor system includes a shaft, which runs through the entire pump body. Both ends of the shaft are supported by bearing bodies. Two first-stage impellers are sequentially provided on the surface of the shaft. A split volute is provided between the two first-stage impellers. The first-stage impeller and the first-stage guide vane body cooperate to form a pump stage. The two first-stage impellers are installed in series and connected through a flow channel cavity to achieve parallel operation of the two first-stage impellers.

[0005] Preferably, the rotor system further comprises a secondary impeller, wherein the secondary impeller is mounted on the shaft, the secondary impeller cooperates with the secondary guide vanes, and is sealed by a secondary sealing ring.

[0006] Preferably, the rotor system further comprises a final-stage impeller, which is mounted on the shaft and disposed at the rear end of the secondary impeller.

[0007] Preferably, a balancing drum is provided in the middle of the shaft, the balancing drum is cooperatively connected with the balancing seat, one end of the balancing seat is provided with a seat sleeve pressure cover and is arranged in the water outlet section, and the balancing drum is used to balance the axial thrust.

[0008] Preferably: sealing assemblies are provided at both ends of the pump body, the sealing assemblies include a sealing body and a dustproof disc, a sealing pressure cover is provided on one side of the sealing body, the sealing body and the pump cover are fixedly connected by bolts, and the dustproof disc is sleeved on the outside of the shaft.

[0009] Preferably, the bearing body is fixedly connected to the pump cover via a connecting piece, and a rolling bearing is provided inside the bearing body, and the rolling bearing is used to support the rotation of the shaft.

[0010] Preferably, a bearing end cover is provided on the outer side of the bearing body, and the bearing end cover is used to seal and protect the bearing body.

[0011] Preferably: the first-stage impeller is sealed by a first-stage sealing ring, the liquid enters the pump body from the water inlet section, flows into the middle section after being pressurized by the first-stage impeller, and is introduced into the secondary impeller for pressurization through the first-stage guide vane body, and finally is introduced into the water outlet section by the last-stage guide vane and discharged from the discharge port.

[0012] Compared with the existing technology, the technical solution proposed in this application has the following beneficial effects: two smaller first-stage impellers are used, provided that the design flow rate of the two first-stage impellers is 1 / 2 of the design flow rate of the water pump; the two first-stage impellers are installed in series and are each individually equipped with guide vanes; the first guide vane outlet and the second guide vane outlet are connected through a flow channel cavity, thereby realizing the state of two small first-stage impellers running in parallel; thereby, a single first-stage impeller only needs to bear 1 / 2 of the pump operating flow rate, and its cavitation performance can also be greatly reduced; the final cavitation margin can be consistent with the traditional first-stage double-suction staged multi-stage pump, but the structure is more compact and simpler, and the efficiency is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings: Figure 1 It is the overall structural diagram of the present invention; In the figure: 1. Water inlet section, 2. Diverter volute, 3. Book discharge section, 4. Middle section, 5. Shaft, 6. First-stage impeller, 7. First-stage sealing ring, 8. First-stage guide vane body, 9. Secondary impeller, 10. Secondary guide vane, 11. Through-bar bolt, 12. Secondary sealing ring, 13. Balance drum, 14. Balance seat, 15. Seat sleeve gland, 16. Pump cover, 17. Bearing body, 18. Rolling bearing, 19. Bearing end cover, 20. Dustproof disc, 21. Seal body, 22. Seal gland, 23. Impeller retaining sleeve, 24. Last-stage guide vane. DETAILED DESCRIPTION

[0014] The following will clearly and completely describe and discuss the technical solutions in the embodiments of the present invention in conjunction with the drawings of the present invention. Obviously, what is described here is only a part of the examples of the present invention, not all the examples. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0015] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a central component. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a central component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a central component. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0017] See also Figure 1 A new type of low-cavitation segmented multi-stage pump comprises: a casing guide structure, wherein the casing guide structure comprises a pump cover, an inlet section, several middle sections and an outlet section, the inlet section, the middle section and the outlet section are sealed and connected in sequence, and are fixed by passing through rod bolts through each section; a rotor system, wherein the rotor system comprises a shaft, the shaft passes through the entire pump body, and the two ends of the shaft are supported by bearing bodies, and two first-stage impellers are provided on the surface of the shaft in sequence, and a diverter volute is provided between the two first-stage impellers, and the first-stage impeller cooperates with the first-stage guide vane body to form a pump stage, and the two first-stage impellers are installed in series and connected through a flow channel cavity to realize the parallel operation of the two first-stage impellers.

[0018] The rotor system further includes a secondary impeller mounted on the shaft, the secondary impeller cooperating with secondary guide vanes and sealed by a secondary sealing ring. The rotor system further includes a final impeller mounted on the shaft and disposed at a rear end of the secondary impeller.

[0019] A balancing drum is installed in the middle of the shaft and is mated with the balancing seat. One end of the balancing seat is equipped with a seat cover and is located in the water outlet section. The balancing drum is used to balance axial thrust. Seal assemblies are installed at both ends of the pump body. These assemblies include a sealing body and a dustproof disc. A sealing cover is installed on one side of the sealing body. The sealing body and the pump cover are fixedly connected by bolts. The dustproof disc is sleeved on the outside of the shaft.

[0020] The bearing body is fixedly connected to the pump cover via a connector, a rolling bearing is provided inside the bearing body, and the rolling bearing is used to support the rotation of the shaft. A bearing end cover is provided on the outside of the bearing body, and the bearing end cover is used to seal and protect the bearing body.

[0021] The first-stage impeller is sealed by a first-stage sealing ring, and an impeller sleeve is also installed between the first-stage impeller and the shaft. Liquid enters the pump body from the water inlet section, is pressurized by the first-stage impeller, flows into the middle section, and is introduced into the secondary impeller for further pressurization through the first-stage guide vanes. Finally, it is introduced into the water outlet section by the final-stage guide vanes and discharged from the outlet. The original segmented multi-stage pump's first-stage impeller is modified to two smaller first-stage impellers, provided that the design flow rate of the two first-stage impellers is 1 / 2 of the pump's design flow rate. The two mobile impellers are installed in series and each is equipped with a separate guide vane. The first guide vane outlet and the second guide vane outlet are connected through a flow channel cavity, thereby achieving a state where the two small first-stage impellers operate in parallel. This ensures that a single first-stage impeller only needs to bear 1 / 2 of the pump's operating flow rate, and its cavitation performance can be greatly reduced. The final NPSH can be achieved by matching that of a traditional first-stage double-suction staged multi-stage pump, but with a more compact and simpler structure and higher efficiency.

[0022] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and that one or more of the above embodiments may be combined. Those skilled in the art may make various changes, modifications, or combinations within the scope of the claims, which do not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments may be combined with each other in any manner.

Claims

1. A new type of low cavitation segmented multistage pump, characterized in that: include The casing flow guide structure includes a pump cover, a water inlet section, several middle sections and a water outlet section. The water inlet section, the middle section and the water outlet section are sealed and connected in sequence and fixed by through-rod bolts that penetrate through each section. The rotor system includes a shaft, which runs through the entire pump body. Both ends of the shaft are supported by bearing bodies. Two first-stage impellers are sequentially provided on the surface of the shaft. A split volute is provided between the two first-stage impellers. The first-stage impeller and the first-stage guide vane body cooperate to form a pump stage. The two first-stage impellers are installed in series and connected through a flow channel cavity to achieve parallel operation of the two first-stage impellers.

2. A novel low cavitation segmented multistage pump according to claim 1, characterized in that: The rotor system further includes a secondary impeller mounted on the shaft. The secondary impeller cooperates with the secondary guide vanes and is sealed by a secondary sealing ring.

3. A novel low cavitation segmented multistage pump according to claim 2, characterized in that: The rotor system further includes a final-stage impeller mounted on the shaft and disposed at the rear end of the secondary impeller.

4. A novel low cavitation segmented multi-stage pump according to claim 3, characterized in that: A balancing drum is provided in the middle of the shaft, and the balancing drum is cooperatively connected with the balancing seat. One end of the balancing seat is provided with a seat sleeve pressure cover and is arranged in the water outlet section. The balancing drum is used to balance the axial thrust.

5. A novel low cavitation segmented multi-stage pump according to claim 4, characterized in that: Sealing assemblies are provided at both ends of the pump body, and the sealing assemblies include a sealing body and a dustproof disc. A sealing gland is provided on one side of the sealing body. The sealing body and the pump cover are fixedly connected by bolts, and the dustproof disc is sleeved on the outside of the shaft.

6. A novel low cavitation segmented multi-stage pump according to claim 5, characterized in that: The bearing body is fixedly connected to the pump cover via a connecting piece. A rolling bearing is provided inside the bearing body, and the rolling bearing is used to support the rotation of the shaft.

7. A novel low cavitation segmented multi-stage pump according to claim 6, characterized in that: A bearing end cover is provided on the outer side of the bearing body, and the bearing end cover is used to seal and protect the bearing body.

8. A novel low cavitation segmented multi-stage pump according to claim 7, characterized in that: The first-stage impeller is sealed by the first-stage sealing ring. The liquid enters the pump body from the water inlet section, flows into the middle section after being pressurized by the first-stage impeller, and is introduced into the secondary impeller for pressurization through the first-stage guide vane body. Finally, it is introduced into the water outlet section by the last-stage guide vane and discharged from the discharge port.

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